Conventionally, there is known an image-recording apparatus that includes a main tank storing liquid, a sub tank for storing the liquid supplied from the main tank, and a head provide with nozzles for ejecting the liquid supplied from the sub tank. For example, Japanese Patent Application Publication No. 2008-213162 (Reference 1) discloses such an image-recording apparatus in which both of the main tank and the sub tank are open to an atmosphere. Accordingly, when a liquid level of the liquid stored in the sub-tank is lowered due to ejection of the liquid at the head, there is generated a water head difference between a liquid level of the liquid stored in the main tank and the liquid level of the liquid stored in the sub tank. Due to this water head difference, the liquid stored in the main tank is allowed to flow into the sub-tank.
On the other hand, Japanese Patent Application Publication No. 2014-180797 (Reference 2) discloses a liquid cartridge whose liquid chamber is divided into an upper space and a lower space by a partitioning wall. In this liquid cartridge, the partitioning wall is formed with a connecting port through which liquid in the upper space is allowed to flow into the lower space.